1982 CB750F...Better Devil

esmoojee

New Member
Re: 1982 CB750F Resto-mod. At least that's the current plan.

Here’s a cheaper shock option for you.... http://chrislivengood.net/wp/product/honda-cb-rfy-kit/
 

Jimbonaut

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Re: 1982 CB750F Resto-mod. At least that's the current plan.

esmoojee said:
Here’s a cheaper shock option for you.... http://chrislivengood.net/wp/product/honda-cb-rfy-kit/
Thanks for the link mate, I've come across those RFY shocks before. These are rebuilt and modded? Interesting - always liked the look of piggyback shocks but either a. couldn't afford Ohlins or b. wasn't sure how good the Chinese versions were. Not sure how good these ones are, but they sure look the part.
 

Jimbonaut

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Re: 1982 CB750F Resto-mod. At least that's the current plan.

Thanks in no small part to the advice I got with my last CB build, getting the motor out this time was a breeze. Mobius recommended keeping both wheels on to allow for easier tip-over-ability so that's what I did, but not before loosening up (fork, engine mount nuts, swing arm nut) or removing (rear shock, frame section) everything on the right hand side of the bike. That way, when the things lying on its side, you haven't got a bunch of crap getting in the way from lifting the frame off the engine -



I also removed the front sprocket and unhooked the chain from it - that way I can pull the rear wheel and swing arm off the bike once it's lying on its side. Less weight when it comes to lifting the frame off. The only engine bolts that I kept in place were these -



Tipped her over, removed the swing arm/rear wheel and forks/front wheel and lifted the frame outta there. Me and a mate hauled the lump onto the workbench and job's a good'un





At first glance the engine cases all seem to be in good knick, no busted fins, all good. Moving right along.

Sunday evening. Here beer here.
 

Jimbonaut

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DOTHETON.com: "Anyone seen that charlatan impersonating a restoration in this forum section?"
My CB: "I'll get my coat".
 

teazer

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Other people in the room " We don't care if he's in the wrong room. he can stay right where we can find him." :)
 

Jimbonaut

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Early days, and still not sure how deep I'm going to go into the engine. This'll sound messed up but if the compression hadn't been so good (165psi) across all four cylinders then I'd probably seize that as an opportunity to roll my sleeves up and have a crack at an engine disassembly. Working on the KLR was a great lesson, and its single cylinder was an excellent learning curve - I suppose in truth I'm looking for a reason to get stuck into this inline four. The cam chain sounds pretty loose in there so maybe that could be my excuse? Any advice would be very welcome as always.

It would also give me the opportunity to clean up the engine cases, maybe try some vapour blasting as well, and have a go at painting the thing.

It's a long, long winter here in Montreal - time is on my side.

Unless the wife pulls the trigger on the seat sale to Guadeloupe in January ($150 per person? Rude not to). Then I may get a week off for good behaviour.
 

irk miller

You've been mostly-dead all day.
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Do the routine maintenance, but don't break it down unless you have to. No reason to look for trouble.
 

Jimbonaut

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irk miller said:
Do the routine maintenance, but don't break it down unless you have to. No reason to look for trouble.
Irk, if it's not too much to ask, could you give me the bullet points of routine maintenance? Like a checklist of what to go through? It would be an invaluable resource for me and a huge help in knowing I wasn't overlooking anything. Thanks man.
 

irk miller

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Honestly, just oil, plugs, timing, valve lash. If it runs well, and you have good compression, no smoking, etc. I wouldn't do much else. If riding shows your clutch checks out fine, then ride it til is goes. If the carbs need work, then clean them and replace any rubber. Otherwise, I'd let them go too, if it's running well. I'm all about fixing things when broken, but just because it's old doesn't mean it needs fixed. This DR370 I have is a solid runner. I'm doing some performance mods, like going to a VM carb, and changing the exhaust. But I have no intention on cracking open the motor because it's a good runner.
 

Jimbonaut

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Nice one, thanks mate. This for sure helps, and you guys are right - no sense in fixing stuff that ain't busted.

Once I pull the valve cover I'll check the valve clearances, and I'll also check the tension on the two cam chains. Offline, I've been told conflicting things about replacing the valve seals. On the one hand I've been told replacing the seals is a good idea, but on the other I've been cautioned that replacing the seals will alter the compression in the top half of the engine which would then mean replacing the piston rings as well. Or something like that (it was all in French - my French is iffy at best).

First off, before doing anything, I'm going to shine a light into the exhaust ports and see if I can see any oil on the valve stems. If I can't I think I'll leave well enough alone. If I can I'll probably replace the valve seals. What's the common consensus on doing this - would I also need to replace the piston rings as well? Again, with such good compression in the engine I'd rather not.
 

irk miller

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I don't understand how valve seals have anything to do with your compression. They keep oil from entering the combustion chamber. They're on the cam side of the motor, not the combustion chamber side. If they don't leak, keep running them until they do. With your compression numbers, it appears the valves don't leak either.
 

adventurco

Nick Ol' Eye
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The Jimbonaut said:
Nice one, thanks mate. This for sure helps, and you guys are right - no sense in fixing stuff that ain't busted.

Once I pull the valve cover I'll check the valve clearances, and I'll also check the tension on the two cam chains. Offline, I've been told conflicting things about replacing the valve seals. On the one hand I've been told replacing the seals is a good idea, but on the other I've been cautioned that replacing the seals will alter the compression in the top half of the engine which would then mean replacing the piston rings as well. Or something like that (it was all in French - my French is iffy at best).

First off, before doing anything, I'm going to shine a light into the exhaust ports and see if I can see any oil on the valve stems. If I can't I think I'll leave well enough alone. If I can I'll probably replace the valve seals. What's the common consensus on doing this - would I also need to replace the piston rings as well? Again, with such good compression in the engine I'd rather not.
I don't think whoever gave you that advice knows what they're talking about. Bad valve seals, as irk said, only allow oil to enter the combustion chamber resulting in some smoke in the exhaust. They have nothing to do with the rings and can be replaced completely independent of each other.

Honestly, I would just leave the engine alone other than the routine stuff. Get it running and ride it, and fix necessary things as you go.
 

Jimbonaut

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Yeah, now it makes sense. Of course - I figured something was getting lost in translation. It's not the first time. I spent the first two years in Montreal asking for a Russian beer instead of a red one. French, merde.
 

Maritime

Well-Known Member
The Jimbonaut said:
Yeah, now it makes sense. Of course - I figured something was getting lost in translation. It's not the first time. I spent the first two years in Montreal asking for a Russian beer instead of a red one. French, merde.
they were probably talking valve "seats" the part the valve seals against in the combustion chamber, not "seals" which keeps oil from leaking into the intake or exhaust when running. with 165 cold compression your valve seats are fine, don't even lap them. And your seals are probably fine too if you don't get smoke on start up or while running.
 

Jimbonaut

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Maritime said:
they were probably talking valve "seats" the part the valve seals against in the combustion chamber, not "seals" which keeps oil from leaking into the intake or exhaust when running. with 165 cold compression your valve seats are fine, don't even lap them. And your seals are probably fine too if you don't get smoke on start up or while running.
Yes! That was it - valve seats.

Language barriers + dicky hearing in my left ear = room for misinterpretation.
 

Jimbonaut

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Fan-fucking-tastic. I think. Like most beer here - even if I pronounce it all fucked up and order something totally wrong, whatever they bring me is generally excellent.

Unless it's white beer, wheat beer, whatever. Undeniably and unwaveringly awful, always. Gose is truly unforgivable too. Had a few porters last night in a local brew pub. Damn they're good. Recently got into porters and milk stouts. Had a peanut milk stout the other week which sounds weird to say and looks weird to write but tastes amazing.

Russian beer huh. The world really opens up fast when you have no idea what the hell you're saying in a foreign language.
 

irk miller

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haha I bet it does. My last drunk was off of oatmeal porter. Stouts and porters are where i live in the cold months.
 

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